Designing of circuit boards such as printed boards is generally conducted through the use of a graphic processing system such as a computer aided design (CAD) system. The arrangement of wiring and the like is determined in consideration of the location and size of components mounted on the circuit board when designing circuit boards. A circuit board is manufactured by using information of the circuit board that is designed with a graphic processing system. The components are mounted on the circuit board to complete a device that includes the circuit board and the components.
However, a high degree of flatness is expected for manufactured circuit boards in order to reduce, for example, connection failures when mounting the components on the circuit board. Moreover, the device that includes the components and the circuit board is installed in a product. A high degree of assembly accuracy may be expected for the device that includes the components and the circuit board due to the recent miniaturization and increasing thinness of the products. Thus, a manufactured circuit board is expected to have a high degree of flatness in order to meet the high degree of assembly accuracy of the device. However, warp in a manufactured circuit board may increase due to increased densities of components and increases in the size of the circuit board. Phenomena such as an increase in component connection failures may occur when a circuit board is warped. When a phenomenon such as an increase in component connection failures occurs, the design stage of the circuit board is reexamined to modify the design of the circuit board in order to address the warp of the circuit board. Therefore, warp in a circuit board is preferably taken into consideration when designing the circuit board with a graphic processing system.
A plurality of conventional techniques, such as those discussed in Japanese Laid-open Patent Publication No. 2005-190206, International Publication Pamphlet No. WO 2008-001922, and International Publication Pamphlet No. WO 01-050356 address the issue of warp in a circuit board. For example, a technique is known that involves using CAD data from a graphic processing system to derive a degree of warp of an outer surface layer of a circuit board and correct wiring and the like on the circuit board to remain within a prescribed value that does not allow phenomena such as an increase in component connection failures to occur when mounting components. Another technique involves using a simulation to derive an amount of warp generated due to heating of the outer surface layer of a circuit board. Still another technique involves deriving a temperature distribution inside a reflow furnace and modifying the positions of components to keep the outer surface layer of a circuit board within a prescribed range.